Study On Damage Characteristics Of Red Sandstone-concrete The Bi-body Mode In Dry And Saturated State

The interaction between the rock-concrete in the bi-body structure of large-scale civil engineering and hydraulic engineering infrastructure has been a major problem that puzzles the stability of the project.And because of the complex structure of the bi-body mode structures,such as natural water,groundwater and other effects under the influence of the combination of the two structures of the strength and deformation,resulting in the structural nature of the structure itself gradually deteriorated,until the cause of accidents,resulting in personal and Loss of property.Therefore,it is very important to study the mechanical properties and acoustic emission characteristics of rock-concrete the bi-body mode in different water-bearing states,which is of great significance to accurately predict the safety and stability of the bi-body mode engineering.In this paper,the typical red sandstone in Hengyang area is studied by using the self-made model specimen,and the combination of theory and concrete single medium and rock-concrete the bi-body mode compression and acoustic emission test.According to the experimental data,the mechanical properties,deformation characteristics and acoustic emission characteristics of the specimen under dryand saturated state were analyzed to study the effect of water on the damage characteristics of rock-concrete the bi-body mode.The main research work and conclusions are as follows:(1)The stress-strain curves in the dry and saturated state were obtained by the uniaxial compression mechanical properties of the specimens under dry and saturated conditions.The results show that the influence of water on the deformation,uniaxial compressive strength,elastic modulus and failure mode of rock-concrete the bi-body mode is great.The rock-concrete the bi-body mode exhibits a continuous characteristic of the single medium in the process of deformation,and the deformation of the upper and lower parts of the medium is in the form of transverse deformation.(2)The acoustic emission characteristics of the rock-concrete the bi-body mode deformation phase in two states were studied by using the acoustic emission instrument to signal the uniaxial compression process in the dry and saturated state.The results: Under the condition of low load and only a small amount of acoustic emission activity,the acoustic emission characteristic curve shows a significant growth trend when the load reaches about 10% of the peak intensity,There is a large number of acoustic emission activities,and then the speed of falling,to maintain a low acoustic emission rate until the load reaches the peak intensity of about 80%,once again a sharp rise in the test before a period of time crack stability,sound The emissivity is low,and then the deformation has reached the plastic yield stage.The internal crack of the modelspecimen is obviously expanded and the acoustic emission activity is strong.(3)According to the mechanical properties and acoustic emission characteristics of the specimen under dry and saturated state,combined with the microscopic theoretical analysis,the relationship between the mechanical parameters and the acoustic emission parameters was studied,and the damage constitutive model was established based on the study of the evolution of acoustic emission.The stress-stain curve fitted by the constitutive model agrees with the actual stress-stain curve to verify the rationality of the theoretical model.